The light-gathering power, resolution, and signal-to-noise ratio of a light telescope improve as the aperture size of the telescope increases. There is therefore an incentive to build both ground-based and space-based light telescopes with larger aperture sizes. On the other hand, as the aperture size increases, the difficulties in fabricating the necessary optical components of the required optical perfection increases. The bulk and weight of the telescope also increase for larger aperture sizes, which may be a significant limitation for a space-based telescope.
The current goal is to build the next-generation light telescope for space applications with an aperture of 10 meters or more in diameter. (For comparison, the aperture of the monolithic Hubble space telescope is 2.4 meters.) It is unlikely that a monolithic light telescope with a 10 meter aperture could be constructed and transported from earth to space using available launch systems. One alternative design approach is a phased-array telescope having multiple sub-telescopes whose outputs are combined together.
The available designs for a phased-array telescope have significant limitations. With these designs, it is difficult to accomplish the beam combining of the individual light subtelescopes. Additionally, there is not a real exit pupil that permits the inclusion in the phased-array telescope of a dewar-contained infrared imaging sensor with a cold shield.
There is a need for an improved approach to a phased-array telescope. The present invention fulfills this need, and further provides related advantages.